<!DOCTYPE html>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html">
	<meta charset="utf-8" />
	<meta http-equiv="X-UA-Compatible" content="IE=edge" />
	<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
	<title></title>
</head>
<body erke-hide>
</body>
<script>
/**
 * @param {number} num
 * @return {number}
 */
var addDigits = function(num) {
	while(num>=10){
		num=sum(num.toString().split(''));
	};	
	console.log(num);
	return num;
};
function sum(arr){
	var res=0;
	for(var i=0;i<arr.length;i++){
		res+=parseInt(arr[i]);
	};
	return res;
};
var res=new addDigits(38);
</script>
</html>